1. Field of the Invention
The present invention relates to a radiation detection element. In particular, the present invention relates to repairing of a defective pixel in a radiation detection element.
2. Description of the Related Art
Recently, radiographic detection elements such as a FPD (flat panel detector), or the like have been put into practice. Such radiographic detection elements have an X-ray sensitive layer disposed on a TFT (Thin Film Transistor) active matrix substrate, and are able to directly convert X-ray information into digital data. Such FPDs have the merit that, in comparison to with previous imaging plates, images can be more immediately checked and video images can also be checked. Consequently, the introduction of FPDs is proceeding rapidly. Various types are proposed for such radiographic detection elements. There are, for example, direct-conversion-type radiographic detection elements that convert radiation directly to charge in a semiconductor layer, and accumulate the charge. There are also indirect-conversion-type radiographic detection elements that first convert radiation into light with a scintillator, such as CsI:Tl, GOS (Gd2O2S:Tb) or the like, then convert the converted light into charge in a semiconductor layer and accumulate the charge.
In the radiation detection element, for example, plural scan lines and plural signal lines are arranged to intersect with each other. Further, in the radiation detection element, pixels each including a charge storage capacitor and a switching element such as a TFT switch are provided in a matrix at intersections of the scan lines and the signal lines.
In a radiation imaging device using the radiation detection element, when a radiation image is imaged, during irradiation of X-rays, an OFF signal is output to each scan line and each switching element is turned OFF. As a result, charges that are generated in a semiconductor layer are accumulated in each charge storage section. When an image is read out, the radiation imaging device sequentially outputs an ON signal to each scan line and reads out the charges that have been accumulated in the charge storage section in each pixel as an electric signal. By converting the read electric signal into digital data, the radiation imaging device obtains a radiation image.
The radiation detection element is formed by depositing various materials on an insulating substrate, and performing individual processes, such as resist coating, exposing, developing, etching, and resist removing.
In a manufacturing process of the radiation detection element, a defect such as a leak or disconnection of line may occur.
As a technology for repairing such defect, Japanese Patent No. 4311693 discloses a technology of electrically isolating a defected pixel. According to this technology, a portion of a line of the switching element is cut by irradiation of laser light to a switching element of the pixel with a defect.
Further, Japanese Patent Application Laid-Open (JP-A) No. 2002-9272 discloses a technology for cutting intersecting portions of a cut signal line and other lines. According to this technology, since laser repairing is performed and a signal line (referred to also as “signal transmission line”) with a defect is electrically isolated from a read circuit, influence to adjacent pixels due to the potential change in the signal line which has been subject to repairing can be suppressed.
JP-A No. 11-233746 discloses a technology for connecting a signal line by welding a defective signal line and bypassing a disconnected portion. JP-A No. 11-233746 also discloses a radiation detection element that has an array of plural pixels arranged in rows and columns, plural scan lines provided along the rows, plural signal lines (also referred to as “data lines”) provided along the columns, and common electrode lines provided parallel to the signal lines. In this radiation detection element, when the signal lines are disconnected, two scan lines and common electrode lines with the disconnection portions therebetween are connected, and a repairing parallel path is formed. According to this technology, the two scan lines and common electrode lines that are used for the repairing parallel path are cut at portions that do not function as the repairing parallel path, to prevent other signals from being input to the repairing parallel path.
By using the technology disclosed in Japanese Patent No. 4311693, a defective pixel may be isolated when a pixel has a defect. However, this technology is not effective when a line defect occurs.
In the technology disclosed in JP-A No. 2002-9272, the intersecting portions of the cut signal line and other lines are also cut. Therefore, in this technology, reading out the charges from all of the pixels that are connected to the cut signal line cannot be preformed, which results to a line defect.
In the technology disclosed in JP-A No. 11-233746, since the repairing parallel path is formed, the two scan lines with the disconnection portions therebetween may be cut. Accordingly, in this technology, the charges of the pixels associated with the cutting portions of the two scan lines can not be read out.